Remove impossible early return from CompositedLayerMapping::updateGraphicsLayerGeometry

This case can never occur. This function is now only called from a full
compositing update, which cleans out all the dirty bits in the z-list. I ran
all the LayoutTests with a CRASH() in this codepath and it never hit.

Review URL: https://codereview.chromium.org/329613002

git-svn-id: svn://svn.chromium.org/blink/trunk@175915 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/rendering/compositing/CompositedLayerMapping.cpp

@@ -595,10 +595,6 @@ void CompositedLayerMapping::updateSquashingLayerGeometry(const LayoutPoint& off
 
 void CompositedLayerMapping::updateGraphicsLayerGeometry(GraphicsLayerUpdater::UpdateType updateType, const RenderLayer* compositingContainer)
 {
-    // If we haven't built z-order lists yet, wait until later.
-    if (m_owningLayer.stackingNode()->isStackingContext() && m_owningLayer.stackingNode()->zOrderListsDirty())
-        return;
-
     if (!shouldUpdateGraphicsLayer(updateType))
         return;